1. Field of the Invention
The invention relates to X-ray contrasting and X-ray protection materials and can be used in the field of medicine, namely in Roentgen equipment intended for the diagnosis and management of various conditions. More specifically, it can be used for the monitoring of endo-prosthetic appliances, internal surgical joints and connections, and of post-surgical areas of the body in order to avoid leaving surgical napkins, tampons or surgical instructions inside the body of a patient. The invention can also be used to select areas to be exposed in the course of radiation therapy, etc., as well as to produce protective uniforms (aprons, smocks, waistcoats, caps, etc.) and protective shields, partitions, protective coatings, isolation materials, etc.
2. Description of the Prior Art
Already known is an X-ray absorbing material as disclosed in Swedish Patent No. 349366, which provides for an artificial rayon thread that contains barium sulfate (BaSO4) as a mechanical impurity (15% through 65% of total mass). However, adding this mechanical impurity to the textile base of the material results in an abrupt reduction of the material's durability.
Also known are X-ray absorbing materials, for example, in the form of threads that contain bismuth oxide, colloidal silver, and iodine derivatives—all in the form of X-ray contrasting impurities added to a polymeric composition (see, for example, the X-ray absorbing materials described in the Abstract of A. V. Vitulsky entitled “Obtaining and researching of synthetic fibers with X-ray contrasting and anti-germ solutions being added at the time of preparation,” Leningrad, 1974). However, an examination of the properties of a textile base containing such impurities reveals that because the homogeneity of the fiber structure is violated, which is caused by the negative influence of particles of contrasting impurity, the physical and mechanical properties of the fibers and threads made on the basis of such impurities are degraded. A textile base containing such impurities lacks durability, and this limits the range of applications this base can have.
Another known example of the prior art is the X-ray absorbing material disclosed in the Bulgarian Certificate of Invention No. 36217 (1980), made in the form of a thread containing a protective coating against X-rays produced from heavy metals that have been derived by means of crystallization from corresponding salt solutions. Unlike the materials mentioned above, this one displays better physical and mechanical properties because the derivation of the coating by crystallization of the heavy metals from solutions does not substantially affect the mechanical properties of the initial material. Nevertheless, the thinness of the coating causes a lessening of X-ray contrasting and X-ray protection properties. Furthermore, after washing, cleaning and so on, the X-ray absorbing coating adheres only weakly to the initial material, and this causes an abrupt reduction of the X-ray contrasting and X-ray protective properties.
Another known example of the prior art is the X-ray absorbing material disclosed in Soviet Certificate of Invention No. 1826173 A6117/56, 17/00, U.S.S.R., (1980), which has the merits of a material in the form of a thread containing the X-ray absorbing coating of heavy metals, but lacks its drawbacks. This is due to the fact that the X-ray absorbing coating is made of ultra-dispersible particles (UDPs) of sizes between 10−6 and 10−7 m and displays such properties as the abnormal weakening of radiation, as stated in “The phenomenon of abnormal reduction of X-radiation by an ultra-dispersible environment” (Diploma No. 4 of the Russian Academy of Natural Sciences, priority date—May 7, 1987). The metal-containing element (between 10−6 and 10−7 m in size), a finely dispersible mixture of this material, is bonded to the surface of the thread, i.e., on the surface of the textile base. However, the use of a finely dispersible mixture only in the range of ultra-dispersible particles (between 10−6 and 10−7 m in size) that are chemically and physically fissile and pyrophoric, combustible is technologically problematic because it requires special conditions of manufacture, transport, storage and technological application.
The recent discovery in the field of physics of the poly-dispersed environment, entitled “The phenomenon of the abnormal alteration by mono- and multiple environments of permeating radiation quantum stream intensity” (Diploma No. of the Russian Academy of Natural Sciences, priority date—Sep. 19, 1996) caused the discovery that the poly-dispersed environment, assuming that a certain level of dispersibility of particles and segregation thereof by intermixing is ensured, displays a capacity for an abnormally high reduction of X-ray radiation. This is caused by the fact that the poly-dispersed particles, having a size of between one thousandth and hundreds of micrometers, organize themselves into energetically interconnected X-ray absorbing groups. (“The segregation of poly-dispersed particles” means an irregular distribution of the poly-dispersed particles caused by the intermixing of the mixture that is due to the particles' self-organization into a system of energetically interconnected groups, ensuring an increase in photo-absorption.) It is generally known in modern engineering that the use of poly-dispersed mixtures that consist of particles having a size of between 10−9 through 10−3 m does not require any specific limitations and is not fraught with specific technological difficulties in manufacture, transport, storage and use.
U.S. Pat. No. 3,239,669 discloses an X-ray absorbing material containing a rubber matrix with a fixed X-ray absorbing filler. According to this patent, X-ray absorbing elements in the form of lead, bismuth, silver and tungsten can be used as a filler. The main drawback of this example of the prior art is that it reduces the solidity of the material by a factor of two to three times due to the fact that the absorbing particles of filler have a negative influence by violating the uniform structure of the original polymeric mass.
U.S. Pat. No. 2,153,889 discloses other X-ray absorbing materials. These contain a matrix with a fixed X-ray absorbing filler or in the form of gold tubes. U.S. Pat. No. 3,194,239 discloses an X-ray absorbing material in the form of a wire consisting of alloys that contain silver, bismuth, tantalum, wherein the wire and the matrix are fastened together by interweaving and forming a kind of textile thread. Materials containing a matrix with a fixed X-ray absorbing filler of wire made of silver-, bismuth-, tantalum-containing alloys where the wire and matrix are fastened together by interweaving and form a textile thread are preferable to the materials disclosed in U.S. Pat. No. 2,153,889, with regard to their solidity, but have a lower plasticity. This lower plasticity is inadmissible in many cases.
Also known are materials that protect from the impact of X-ray and gamma radiation with heavy fillers, the most widespread of which is lead (See “Technical headway in atomic engineering.” In Isotopes in the U.S.S.R., vol. 1 (72), p. 85). A filler (for example, lead) and a matrix (for example, concrete, polymers, etc.) differ greatly in density, and therefore the filler (lead) is spread irregularly along the matrix volume, which results in a decrease in the X-ray absorbing properties of the material as a whole.
United Kingdom Patent No. 1260342, G 21 F 1/10 discloses an X-ray absorbing material produced on the basis of a polysterol polymeric matrix and a lead-containing organic filler. This material has the same drawback as the lead-containing fillers described in “Technical headway in atomic engineering.” cited above—it also shows an irregular distribution of a heavy X-ray absorbing filler inside the matrix, the material of which has a considerably lower density than the material of the filler.
Closest to the present invention is Russian Federation Patent No. 2053074 G21 F 1/10 of Jun. 27, 1996 (prototype), which discloses an X-ray absorbing material containing a matrix with a fixed X-ray absorbing metal-containing filler in the form of dispersed particles. The drawback of this material is that the addition of a lead-containing filler to a textile base results in a reduction of the density of the material due to the violation of the uniform structure of the textile base that in turn limits the possibility of using the material for the manufacture of various protective articles. A material made on the basis of a thread with lead-containing filler cannot be used as an X-ray contrasting material in the practice of medical radiology due to the lead's toxic properties. Furthermore, it is impossible to effectively and compactly protect against X-ray and gamma-radiation on the basis of such material as a thread (see Russian Federation Patent No. 2063074), and in this case, in order to use the material made from thread it is necessary to apply the special technology of dense, multi-layer machine knitting for the manufacture of multipurpose protective textile tissue. In this way, however, because the narrow bundle of quanta by a stratum of material having a width=X weakens exponentially, in compliance with the described rules set forth in Methods of radiation granulometry and statistical simulation in research on the structural properties of composite materials (V. A. Vorobiev, B. E. Golovanov, S. I. Vorobieva; Moscow: Energoatomizdat, 1984), there occurs a reduction in radiation intensity:I=Io e−μx  (1)WhereI is the intensity of radiation that passes through a stratum of material having a width=X,Io is the intensity of the initial radiation,μ is the linear factor of radiation reduction (weakening; the tabular regulated value for each of the X-ray absorbing materials).
Another drawback of this example of the prior art consists of the high percentage of the metal-containing filler in the total amount of the X-ray absorbing material (a percentage of 66%–89%). This causes an increase in the mass of X-ray absorbing material as a whole, and, on the other hand, the articles made out of this material and heavy and inconvenient to maintain. Still a further drawback of this example of the prior art is the irregular distribution of the heavy filler in the matrix volume.